Higher octane does have to do with MPG. Reason being is it does not burn as fast as a lower rated octane gasoline. There are plenty of people who use premium in there low octane vehicles to obtain not only better gas mileage but a better quality fuel. I also have seen the difference in my dd saturn. And i actually hammered on it to see if it was the placebo effect. Numbers speak for them self. just my
.02 <img src="/forums/images/graemlins/cheers.gif" alt="" />

92 Galant VR4 #501/1k - Turbo, All Wheel Drive with 4 wheel steering - Money eatin toy
89 Isuzu I-Mark RS sings to 7800 RPM - Daily Driver